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Almost every automatic entry/exit barrier control system will feature an inductive loop vehicle detector.
A special cable is buried beneath the roadway, and it is this "coil" connected to the detector itself, located inside the barrier, which can be used to sense the presence, direction of travel, arrival or departure of a range of vehicles, thereby providing automatic actuation of a barrier, or only a part of its access control system.
These signals can be utilized to:
* Arm card readers, coin or token acceptors.
* Signal a barrier to open (Auto exit for example).
* Signal a barrier to close.
* Generate a pulse count to calculate the number of vehicles on site. To activate signs or warning lights.
* To prevent closure of a barrier onto a vehicle.
* To sense the direction of travel (creating an audit of vehicles on site once more).
* Instruct a ticket machine to issue a ticket.
These features are determined by the position of the loop or loops in the roadway, the sensitivity and frequency setting of the detector, the number of cable turns in the loop, and also the shape of the loop itself. Further considerations relate to whether the detector is sensing vehicle presence only, giving a pulse on approach or departure, or whether it has sequential loop polling capability and selectable relay output configuration.
This often over simplified piece of equipment is almost a science in itself, and can be the single most common cause of system failure or poor performance if not correctly specified and installed.
We offer a range of detectors which incorporate all of these features and more besides.
We will also install the system fully, inclusive of slot cutting, cable laying and backfilling. We can even offer surface mounted inductive loops for temporary usage only, thereby making temporary access control more affordable and less hassle!
Please refer to our standard drawing sheets for further details of the most commonly used loop configurations, or contact our sales department to discuss your own particular requirements.